if a single E coli cell is placed on a LB agar plate in the

if a single E. coli cell is placed on a LB agar plate in the final stage of the quadrant streak method,

a) how many cells would make up the resulting colony after two hours and after 24 hours of incubation at 37C?

b) can you prove your results? explain why yes or no!

Solution

(a)             Number of cells after 2 hours= 64

Number of cells after 24 hours= 4,722,366,482,869,645,213,696

(b)

Doubling time of E.coli = 20 minutes

Therefore a single cell will make following number of cells:

In 2 hours

1 hours = 60 minutes

Doubling cycles in 2 hours = 2*60/20 = 6

Therefore number of cells in 2 hours = 2⁶ = 64

In 24 hours

Doubling cycles in 24 hours = 24*60/20 = 72

Therefore number of cells in 24 hours = 2⁷² = 4,722,366,482,869,645,213,696